WASHINGTON — The Supreme Court on Friday allowed a challenge to a Texas abortion law that banned most abortions in the state after about six weeks to proceed, ruling that abortion providers in the state may sue some state officials in federal court despite the procedural hurdles imposed by the unusual structure of the law.

But the Supreme Court refused to block the law in the meantime, saying that lower courts should consider the matter.

The development was both a victory for and a disappointment to supporters of abortion rights, who had hoped that the justices would reverse course from a Sept. 1 ruling that had allowed the law to go into effect, causing clinics in the state to curtail performing the procedure and forcing many women seeking abortions to travel out of state.

The decision in the Texas case came less than two weeks after the court heard a direct challenge to the right to abortion established in 1973 in Roe v. Wade, in a case about a Mississippi law that bans most abortions after 15 weeks. Roe prohibits states from banning abortion before fetal viability, the point at which fetuses can sustain life outside the womb, or about 23 to 24 weeks into a pregnancy.

The court’s six-member conservative majority seemed prepared to uphold the Mississippi law, and several justices indicated that they would vote to overrule Roe outright. A decision in the case is not expected until late June.

The Texas law flouts Roe’s viability line by barring abortions once fetal cardiac activity can be detected, usually around 6 weeks.

The challenges to the Texas law focused not on the law’s constitutionality but on whether the law could be challenged in court by either abortion providers in the state or the federal government. The cases provided the court with an opportunity to revisit its earlier decision allowing the law to go into effect before the justices had grappled with its constitutionality or settled the question of how it could be challenged.

The Texas law, known as Senate Bill 8, has unusual features.

Usually, a lawsuit seeking to block a law because it is unconstitutional would name state officials as defendants. However, the Texas law, which makes no exceptions for pregnancies resulting from incest or rape, bars state officials from enforcing it and instead deputizes private individuals to sue anyone who performs the procedure or “aids and abets” it.

The patient may not be sued, but doctors, staff members at clinics, counselors, people who help pay for the procedure or drive them to it are all potential defendants. Plaintiffs, who do not need to live in Texas, have any connection to the abortion or show any injury from it, are entitled to $10,000 and their legal fees recovered if they win. Prevailing defendants are not entitled to legal fees.

The court’s earlier encounter with the law left the justices bitterly divided, with Chief Justice John G. Roberts Jr. joining the court’s three more liberal members in dissent.

The majority opinion, issued just before midnight on Sept. 1, was unsigned and consisted of a single long paragraph. It said the abortion providers who had challenged the law in an emergency application had not made their case in the face of “complex and novel” procedural questions. The majority stressed that it was not ruling on the constitutionality of the Texas law and did not mean to limit “procedurally proper challenges” to it.

Each of the dissenting justices issued an opinion in that earlier ruling.

“The court’s order is stunning,” Justice Sonia Sotomayor wrote, for instance. “Presented with an application to enjoin a flagrantly unconstitutional law engineered to prohibit women from exercising their constitutional rights and evade judicial scrutiny, a majority of justices have opted to bury their heads in the sand.”

“The court has rewarded the state’s effort to delay federal review of a plainly unconstitutional statute, enacted in disregard of the court’s precedents, through procedural entanglements of the state’s own creation,” Justice Sotomayor wrote. “The court should not be so content to ignore its constitutional obligations to protect not only the rights of women, but also the sanctity of its precedents and of the rule of law.”

The case returned to the Supreme Court on two separate tracks. After the court rejected the providers’ request for emergency relief, the Justice Department filed its own challenge to the law, one that it said was not subject to the procedural barriers the providers had faced. The case soon reached the Supreme Court on an emergency application.

The abortion providers also returned to the court, asking the justices to use an unusual procedure — “certiorari before judgment” — to leapfrog the appeals court and decide whether they were entitled to sue.

The Supreme Court agreed to decide both cases on Oct. 22, putting them on an extraordinarily fast track. It heard arguments just 10 days later, on Nov. 1, focusing on the question of whether the providers and the government were entitled to sue in light of the law’s unusual structure.

At those arguments, two members of the original majority, Justices Brett M. Kavanaugh and Amy Coney Barrett, asked questions suggesting that they might have had a change of heart about the law.